kubkon review changes: 3

- make vendored settings failure unreachable
- rename field `darwinSdkLayout` → `darwin_sdk_layout`
- make `darwin_sdk_layout` optional

src/Compilation.zig

@@ -1557,7 +1557,7 @@ pub fn create(gpa: Allocator, options: InitOptions) !*Compilation {
             .link_libc = link_libc,
             .link_libcpp = link_libcpp,
             .link_libunwind = link_libunwind,
-            .darwinSdkLayout = libc_dirs.darwinSdkLayout,
+            .darwin_sdk_layout = libc_dirs.darwin_sdk_layout,
             .objects = options.link_objects,
             .frameworks = options.frameworks,
             .framework_dirs = options.framework_dirs,
@@ -5287,7 +5287,7 @@ fn detectWin32ResourceIncludeDirs(arena: Allocator, options: InitOptions) !LibCD
                 .libc_installation = null,
                 .libc_framework_dir_list = &.{},
                 .sysroot = null,
-                .darwinSdkLayout = .none,
+                .darwin_sdk_layout = null,
             },
         }
     }
@@ -5656,7 +5656,7 @@ const LibCDirs = struct {
     libc_installation: ?*const LibCInstallation,
     libc_framework_dir_list: []const []const u8,
     sysroot: ?[]const u8,
-    darwinSdkLayout: link.DarwinSdkLayout,
+    darwin_sdk_layout: ?link.DarwinSdkLayout,
 };
 
 fn getZigShippedLibCIncludeDirsDarwin(arena: Allocator, zig_lib_dir: []const u8) !LibCDirs {
@@ -5672,7 +5672,7 @@ fn getZigShippedLibCIncludeDirsDarwin(arena: Allocator, zig_lib_dir: []const u8)
         .libc_installation = null,
         .libc_framework_dir_list = &.{},
         .sysroot = null,
-        .darwinSdkLayout = .vendored,
+        .darwin_sdk_layout = .vendored,
     };
 }
 
@@ -5690,7 +5690,7 @@ pub fn detectLibCIncludeDirs(
             .libc_installation = null,
             .libc_framework_dir_list = &.{},
             .sysroot = null,
-            .darwinSdkLayout = .none,
+            .darwin_sdk_layout = null,
         };
     }
 
@@ -5748,7 +5748,7 @@ pub fn detectLibCIncludeDirs(
         .libc_installation = null,
         .libc_framework_dir_list = &.{},
         .sysroot = null,
-        .darwinSdkLayout = .none,
+        .darwin_sdk_layout = null,
     };
 }
 
@@ -5803,7 +5803,7 @@ fn detectLibCFromLibCInstallation(arena: Allocator, target: Target, lci: *const
         .libc_installation = lci,
         .libc_framework_dir_list = framework_list.items,
         .sysroot = sysroot,
-        .darwinSdkLayout = if (sysroot == null) .none else .sdk,
+        .darwin_sdk_layout = if (sysroot == null) null else .sdk,
     };
 }
 
@@ -5865,7 +5865,7 @@ fn detectLibCFromBuilding(
         .libc_installation = null,
         .libc_framework_dir_list = &.{},
         .sysroot = null,
-        .darwinSdkLayout = .vendored,
+        .darwin_sdk_layout = .vendored,
     };
 }
 

src/link.zig

@@ -137,7 +137,7 @@ pub const Options = struct {
     link_libc: bool,
     link_libcpp: bool,
     link_libunwind: bool,
-    darwinSdkLayout: DarwinSdkLayout,
+    darwin_sdk_layout: ?DarwinSdkLayout,
     function_sections: bool,
     no_builtin: bool,
     eh_frame_hdr: bool,
@@ -285,8 +285,6 @@ pub const CompressDebugSections = enum { none, zlib };
 
 /// The filesystem layout of darwin SDK elements.
 pub const DarwinSdkLayout = enum {
-    /// Does not apply to the target.
-    none,
     /// macOS SDK layout: TOP { /usr/include, /usr/lib, /System/Library/Frameworks }.
     sdk,
     /// Shipped libc layout: TOP { /lib/libc/include,  /lib/libc/darwin, <NONE> }.

src/link/MachO.zig

@@ -652,8 +652,7 @@ pub fn resolveLibSystem(
             "libSystem",
         )) break :success;
 
-        switch (self.base.options.darwinSdkLayout) {
-            .none => unreachable,
+        switch (self.base.options.darwin_sdk_layout.?) {
             .sdk => {
                 const dir = try fs.path.join(tmp_arena, &[_][]const u8{ self.base.options.sysroot.?, "usr", "lib" });
                 if (try accessLibPath(tmp_arena, &test_path, &checked_paths, dir, "libSystem")) break :success;

src/link/MachO/load_commands.zig

@@ -474,19 +474,16 @@ pub fn inferSdkVersion(gpa: Allocator, comp: *const Compilation) ?std.SemanticVe
 
     const options = comp.bin_file.options;
 
-    const sdk_dir = switch (options.darwinSdkLayout) {
-        .none => unreachable,
+    const sdk_layout = options.darwin_sdk_layout.?;
+    const sdk_dir = switch (sdk_layout) {
         .sdk => options.sysroot.?,
         .vendored => std.fs.path.join(arena, &.{ comp.zig_lib_directory.path.?, "libc", "darwin" }) catch return null,
     };
-
     if (readSdkVersionFromSettings(arena, sdk_dir)) |ver| {
         return parseSdkVersion(ver);
     } else |_| {
-        if (options.darwinSdkLayout == .vendored) {
-            // vendored layout does not have versioned pathname
-            return null;
-        }
+        // We control vendored and reading settings should always succeed.
+        if (sdk_layout == .vendored) @panic("zig installation bug: unable to parse SDK version");
     }
 
     // infer from pathname